Microelectronic assembly with joined bond elements having lowered inductance

ABSTRACT

A microelectronic assembly includes a semiconductor chip having chip contacts exposed at a first face and a substrate juxtaposed with a face of the chip. A conductive bond element can electrically connect a first chip contact with a first substrate contact of the substrate, and a second conductive bond element can electrically connect the first chip contact with a second substrate contact. The first bond element can have a first end metallurgically joined to the first chip contact and a second end metallurgically joined to the first substrate contact. A first end of the second bond element can be metallurgically joined to the first bond element. The second bond element may or may not touch the first chip contact or the substrate contact. A third bond element can be joined to ends of first and second bond elements which are joined to substrate contacts or to chip contacts. In one embodiment, a bond element can have a looped connection, having first and second ends joined at a first contact and a middle portion joined to a second contact.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Korean Application No.10-2010-0040446 filed Apr. 30, 2010 and claims the benefit of the filingdate of U.S. Provisional Patent Application No. 61/322,404 filed Apr. 9,2010. This application is a continuation-in-part of U.S. applicationSer. No. 12/644,476, filed Dec. 22, 2009. The disclosures of all of theaforesaid applications are hereby incorporated herein by reference.

BACKGROUND

Microelectronic elements, e.g., semiconductor chips, are typically flatbodies with oppositely facing, generally planar front and rear surfaceswith edges extending between these surfaces. Chips generally havecontacts, sometimes also referred to as pads or bond pads, on the frontsurface which are electrically connected to the circuits within thechip. Chips are typically packaged by enclosing them with a suitablematerial to form microelectronic packages having terminals that areelectrically connected to the chip contacts. The package may then beconnected to test equipment to determine whether the packaged deviceconforms to a desired performance standard. Once tested, the package maybe connected to a larger circuit (e.g. a circuit in an electronicproduct such as a computer or a cell phone) by connecting the packageterminals to matching lands on a printed circuit board (PCB) by asuitable connection method such as soldering.

A common technique used to form electrically conductive connectionsbetween a microelectronic chip and one or more other electroniccomponents is wire-bonding. Conventionally, a wirebonding tool attachesthe end of a wire to a pad on a microelectronic chip using thermaland/or ultrasonic energy and then loops the wire to a contact on theother electronic component and forms a second bond thereto using thermaland/or ultrasonic forces.

SUMMARY

One of the challenges of wire-bond technology is that electromagnetictransmissions along a wire can extend into space surrounding the wire,and can induce currents in nearby conductors and cause unwantedradiation and detuning of the line. Wire-bonds generally are alsosubject to self-inductances and are subject to external noise (e.g. fromnearby electronic components). These challenges can become morepronounced as the pitch between contacts on microelectronic chips andother electronic components becomes smaller, and as the chips operate athigher frequencies.

Various structures and techniques for manufacturing are described hereinfor a microelectronic assembly. In accordance with one embodiment, amicroelectronic device such as a semiconductor chip can be wire-bondedto a package element within a microelectronic assembly such as apackage. In one example, a package element can be a substrate or chipcarrier having a dielectric element and a set of electrically conductivepads exposed at a surface of the dielectric element.

In accordance with one embodiment herein, a microelectronic assembly isprovided which can include a semiconductor chip having a first face, asecond face, and a plurality of chip contacts exposed at the first face.A substrate can be juxtaposed with one of the first or second faces. Thesubstrate can have a plurality of substrate contacts exposed at a faceof the substrate. The assembly can include a first electricallyconductive bond element and a second electrically conductive bondelement. The first and second bond elements can each be one of a bondribbon or a bond wire. The first and second bond elements canelectrically connect a chip contact with a corresponding substratecontact and provide parallel conductive paths between the chip contactand substrate contact. The first bond element can have a first endmetallurgically joined to the chip contact and a second endmetallurgically joined to the substrate contact. The second bond elementcan be metallurgically joined to the first and second ends of the firstbond element. In accordance with a particular embodiment, the secondbond element can be joined to the first bond element in such manner thatit does not touch either the chip contact or the substrate contact.

In accordance with a particular aspect of the invention, the firstelectrically conductive bond element can be a first bond wire and thesecond electrically conductive bond element can be a second bond wire.

In one embodiment, one of the first and second ends of the first bondwire can include a ball, and the second bond wire can include a ball.The ball of the second bond wire can be metallurgically joined to theball of the first bond wire.

In another embodiment, one of the first and second ends of the firstbond wire can include a ball, the second bond wire can have a first endincluding a ball and a second end remote therefrom, and the second endof the second bond wire can be metallurgically joined to the ball of thefirst bond wire.

In accordance with one embodiment, the first bond element can be a leadbond, and the second bond element can be a bond wire.

In accordance with another embodiment herein, a microelectronic assemblyis provided which can include a semiconductor chip having a first face,a second face, and a plurality of chip contacts exposed at the firstface. A substrate can be juxtaposed with one of the first or secondfaces. The substrate can have a plurality of substrate contacts thereon.Such assembly can further include a first electrically conductive bondelement connecting a first pair of a substrate contact and a chipcontact. The first bond element can be a lead bond or a bond wire. Theassembly can further include a second electrically conductive bondelement connecting a second pair of a substrate contact and a chipcontact. The second bond element can also be a lead bond or a bond wire.

A third electrically conductive bond element, being a ribbon bond or abond wire, can be joined to ends of the first and second bond elements.The third bond element can be joined to the first and second bondelements in such manner that it does not touch either the chip contactor the substrate contact.

In accordance with one embodiment, the joints of the third bond elementwith the first and second bond elements can be adjacent the chipcontacts.

In accordance with one embodiment, the joints of the third bond elementwith the first and second bond elements can be adjacent the substratecontacts.

In accordance with one embodiment, each of the first, second and thirdbond elements can be bond wires.

In accordance with one embodiment, the first and second bond elementscan be lead bonds and the third bond element can be a bond wire.

In accordance with one embodiment herein, a microelectronic assembly caninclude a semiconductor chip having a first face, a second face, and aplurality of chip contacts exposed at the first face. A substrate can bejuxtaposed with one of the first or second faces. The substrate can havea plurality of terminals thereon and leads electrically connected withthe terminals and extending away therefrom. At least one of the leadscan have an end bonded to a chip contact exposed at the first face ofthe chip. A bond wire can have a first end metallurgically joined to theend of the lead. The bond wire can be joined in such manner that it doesnot touch the chip contact. The bond wire can have a second end, remotefrom the first end, that is metallurgically joined to the lead at alocation spaced apart from the chip contact.

In accordance with one embodiment, the second end of the bond wire canbe joined to the lead at a location where the lead overlies thesubstrate.

In accordance with one embodiment herein, a microelectronic assembly caninclude a semiconductor chip having a first face, a second face, and aplurality of chip contacts exposed at the first face. A substrate can bejuxtaposed with one of the first or second faces, the substrate having aplurality of substrate contacts thereon. The assembly can furtherinclude a plurality of electrically conductive bond elements. A bondelement can be a bond ribbon or a bond wire, and the bond element canelectrically connect a pair of a chip contact and a correspondingsubstrate contact. At least one bond element can have first and secondends connected to a first contact of such pair of the contacts. A middleportion between the first and second ends can be metallurgically joinedwith the second contact of the pair of contacts. In such way, the atleast one bond element can extend in a continuous loop from the firstend at the first contact, through a joint between the middle portionwith the second contact, and can return in the continuous loop from thesecond contact to the first contact.

In accordance with one embodiment, the second end can be joined to thefirst end such that the second end does not touch the first contact.

In accordance with one embodiment, each of the first and second ends canbe joined directly to the first contact.

In accordance with one embodiment, the at least one bond element can bea bond wire.

In accordance with one embodiment, the at least one bond element can bea bond ribbon. In a particular embodiment of the invention, amicroelectronic assembly is provided in which a semiconductor chip has afirst face, a second face remote from the first face, and a plurality ofchip contacts exposed at the first face. A substrate can be juxtaposedwith one of the first or second faces, the substrate having a pluralityof substrate contacts. The assembly can include a first electricallyconductive bond element and a second electrically conductive bondelement. The first and second bond elements can each be one of a bondribbon or a bond wire, the first bond element electrically connecting afirst chip contact of the plurality of chip contacts with a firstsubstrate contact of the plurality of substrate contacts, and the secondbond element electrically connecting the first chip contact with asecond substrate contact of the plurality of substrate contacts. Thefirst bond element can have a first end metallurgically joined to thefirst chip contact and a second end metallurgically joined to the firstsubstrate contact. The second bond element can have a first endmetallurgically joined to the first bond element so that that the secondbond element does not touch the first chip contact.

In yet another embodiment of the invention, a microelectronic assemblyis provided in which a semiconductor chip has a first face, a secondface remote from the first face, and a plurality of chip contactsexposed at the first face. A substrate can be juxtaposed with one of thefirst or second faces, the substrate having a plurality of substratecontacts. The assembly can include a first electrically conductive bondelement and a second electrically conductive bond element. The first andsecond bond elements can each be one of a bond ribbon or a bond wire,the first bond element electrically connecting a first chip contact ofthe plurality of chip contacts with a first substrate contact of theplurality of substrate contacts, and the second bond elementelectrically connecting the first chip contact with a second substratecontact of the plurality of substrate contacts. The first bond elementcan have a first end metallurgically joined to the first chip contactand a second end metallurgically joined to the first substrate contact.The second bond element can have a first end metallurgically joined tothe first end of the first bond element.

In yet another embodiment of the invention, a microelectronic assemblyis provided in which a semiconductor chip has a first face, a secondface remote from the first face, and a plurality of chip contactsexposed at the first face. A substrate can be juxtaposed with one of thefirst or second faces, the substrate having a plurality of substratecontacts. The assembly can include a first electrically conductive bondelement and a second electrically conductive bond element. The first andsecond bond elements can each be one of a bond ribbon or a bond wire.The first bond element can have a first end metallurgically joined tothe first chip contact and a second end metallurgically joined to thefirst substrate contact. The second bond element can have a first endmetallurgically joined to the first bond element so that it does nottouch the first chip contact. A second end of the second bond elementcan be metallurgically joined to the first substrate contact.

In a variation of such embodiment, the first end of the second bondelement can be metallurgically joined to the first bond element and tothe chip contact.

In accordance with one embodiment of the invention, a microelectronicassembly is provided which includes a semiconductor chip having a firstface, a second face, and a plurality of chip contacts exposed at thefirst face. A substrate can be juxtaposed with one of the first orsecond faces, the substrate having a plurality of substrate contactsexposed at a face of the substrate. The assembly can include a firstelectrically conductive bond wire and a second electrically conductivebond wire, the first and second bond wires electrically connecting afirst chip contact of the plurality of chip contacts with acorresponding first substrate contact of the plurality of substratecontacts and providing parallel conductive paths between the first chipcontact and first substrate contact. The first bond wire can have afirst end metallurgically joined to the first chip contact and a secondend metallurgically joined to the first substrate contact. One of thefirst and second ends of the first bond wire can include a ball, and oneof the first and second ends of the second bond wire can include a ball.The ball of the second bond wire can be metallurgically joined directlyto one of the first and second ends of the first bond wire, in such waythat the second bond wire does not touch either the first chip contactor the first substrate contact.

In accordance with one or more aspects of the invention, the ball of thesecond bond wire can be metallurgically joined to the ball of the firstbond wire. In accordance with another preferred aspect, an end of thesecond bond wire remote from the ball of the second bond wire ismetallurgically joined to the ball of the first bond wire.

In accordance with another embodiment of the invention, amicroelectronic assembly can include a semiconductor chip can have afirst face, a second face, and a plurality of chip contacts exposed atthe first face. A substrate can be juxtaposed with one of the first orsecond faces, the substrate having a plurality of substrate contactsthereon. The assembly can include a first electrically conductive bondelement connecting a first pair of a substrate contact and a chipcontact, and the first bond element can be one of a lead bond or a bondwire, for example. A second electrically conductive bond element canconnect a second pair of a substrate contact and a chip contact, thefirst bond element being one of a lead bond or a bond wire. A thirdelectrically conductive bond element, which can be a ribbon bond or abond wire, for example, can be joined to ends of the first and secondbond elements, wherein the third bond element does not touch the chipcontact or the substrate contact of either the first or second pairs.

In one example, the joints of the third bond element with the first andsecond bond elements can be adjacent the chip contacts of the first andsecond pairs. In another example, the joints of the third bond elementwith the first and second bond elements can be adjacent the substratecontacts of the first and second pairs.

In a particular example, each of the first, second and third bondelements are bond wires. In another example, the first and second bondelements are lead bonds and the third bond element is a bond wire.

A microelectronic assembly in accordance with another embodiment caninclude a semiconductor chip having a first face, a second face, and aplurality of chip contacts exposed at the first face. A substrate can bejuxtaposed with one of the first or second faces, the substrate having aplurality of terminals thereon and a plurality of leads electricallyconnected with the terminals and extending away therefrom. A first leadof the plurality of leads can have an end bonded to a first chip contactof the plurality of chip contacts. A bond wire can have a first endmetallurgically joined to the end of the first lead, the bond wire nottouching the first chip contact, and the bond wire having a second endmetallurgically joined to the first lead at a location spaced apart fromthe first chip contact.

In a particular example, the second end of the bond wire can be joinedto the first lead at a location where the first lead overlies thesubstrate.

In accordance with another embodiment of the invention, amicroelectronic assembly can include a semiconductor chip having a firstface, a second face, and a plurality of chip contacts exposed at thefirst face. A substrate can be juxtaposed with one of the first orsecond faces, the substrate having a plurality of substrate contactsthereon. The assembly can include a plurality of electrically conductivebond elements including a first bond element, the first bond elementbeing a bond ribbon or a bond wire electrically connecting a pair ofcontacts. The pair of contacts can include a chip contact of theplurality of chip contacts and a corresponding substrate contact of theplurality of substrate contacts. The first bond element can have firstand second ends electrically connected to a first contact of the pair ofthe contacts, and a middle portion between the first and second endsmetallurgically joined with the second contact of the pair of contacts.In such assembly, the first bond element may extend in a continuous loopfrom the first end at the first contact, through the middle portionjoined to the second contact and back to the second end connected to thefirst contact.

In one example, the second end of the first bond element can be joinedto the first end. The second end may be joined in such manner that itdoes not touch the first contact. In another example, each of the firstand second ends can be joined directly to the first contact.

In a particular example, the at least one bond element can be a bondwire. In another example, the at least one bond element can be a bondribbon.

A microelectronic assembly in accordance with another embodiment of theinvention can include a semiconductor chip having a first face, a secondface, and a plurality of chip contacts exposed at the first face. Asubstrate can be juxtaposed with one of the first or second faces. Thesubstrate can have a plurality of substrate contacts exposed at a faceof the substrate. The assembly can include a first electricallyconductive bond element and a second electrically conductive bondelement, the first and second bond elements each being one of a bondribbon or a bond wire. The first and second bond elements canelectrically connect a first chip contact of the plurality of chipcontacts with a corresponding first substrate contact of the pluralityof substrate contacts and provide parallel conductive paths between thefirst chip contact and the first substrate contact. The first bondelement can have a first end metallurgically joined to the first chipcontact and a second end metallurgically joined to the first substratecontact. The second bond element can be metallurgically joined to thefirst and second ends of the first bond element.

A microelectronic assembly in accordance with another embodiment of theinvention can include a semiconductor chip having a first face, a secondface remote from the first face, and a plurality of chip contactsexposed at the first face. A substrate can be juxtaposed with one of thefirst or second faces, the substrate having a plurality of substratecontacts. The assembly can include a first electrically conductive bondelement and a second electrically conductive bond element. Each of thefirst and second bond elements can be one of a bond ribbon or a bondwire. The first bond element can electrically connect a first chipcontact of the plurality of chip contacts with a first substrate contactof the plurality of substrate contacts, and the second bond element canelectrically connect the first chip contact with a second substratecontact of the plurality of substrate contacts. The first bond elementcan have a first end metallurgically joined to the first chip contactand a second end electrically connected to the first substrate contact.The second bond element can have a first end metallurgically joined tothe first end of the first bond element so that that the second bondelement does not touch the first chip contact.

In one example, each of the first and second bond elements can be a bondwire. One of the first and second ends of the first bond wire caninclude a ball, and the second bond wire can include a ball. In oneexample, a ball of the second bond wire can be metallurgically joined tothe ball of the first bond wire. In another example, the second bondwire can have a first end including a ball and a second end remotetherefrom, and the second end of the second bond wire can bemetallurgically joined to the ball of the first bond wire.

In one example, at least one of the first or second bond elements can bea bond ribbon.

In a particular example, the microelectronic assembly can furtherinclude a third electrically conductive bond element electricallyconnecting the first substrate contact with the second substratecontact. In one example, the third bond element can be metallurgicallyjoined to a second end of at least one of the first and second bondelements. The third bond element can be metallurgically joined to thesecond ends of each of the first and second bond elements. The thirdbond element can be arranged such that it does not touch any of thefirst or the second substrate contacts to which the first and secondbond elements are bonded.

In one example, the third bond element can be metallurgically joined tothe first and second substrate contacts.

In a particular example, the substrate can overlie the first face of thechip and have an opening exposing the plurality of chip contacts. Thefirst and second bond elements may extend through the opening in thesubstrate.

In a particular example, a second face of the chip can overlie thesubstrate, and the first and second bond elements may extend beyond atleast one edge of the chip.

A microelectronic assembly in accordance with another embodiment of theinvention can include a semiconductor chip having a first face, a secondface remote from the first face, and a plurality of chip contactsexposed at the first face. A substrate can be juxtaposed with one of thefirst or second faces, the substrate having a plurality of substratecontacts. The assembly can include a first electrically conductive bondwire and a second electrically conductive bond wire, the first andsecond bond wires electrically connecting a first chip contact of theplurality of chip contacts with a first substrate contact of theplurality of substrate contacts, and the second bond wire electricallyconnecting the first chip contact with a second substrate contact of theplurality of substrate contacts. The first bond wire can have a firstend metallurgically joined to the first chip contact and a second endmetallurgically joined to the first substrate contact. The second bondwire can have a first end metallurgically joined to the first end of thefirst bond wire.

In one example, the second bond wire can have a first endmetallurgically joined to the first chip contact.

In a particular example, the microelectronic assembly can furtherinclude a third electrically conductive bond element which electricallyconnects the first substrate contact with the second substrate contact.The third bond element can be metallurgically joined to a second end ofat least one of the first and second bond elements.

In one example, the third bond element can be metallurgically joined tothe second ends of each of the first and second bond elements. In oneexample, the third bond element can be metallurgically joined to thefirst and second substrate contacts.

In one example, the substrate may overlie the first face of the chip andhas an opening exposing the plurality of chip contacts. The first andsecond bond elements may extend through the opening in the substrate.

In one example, the second face of the chip can overlie the substrate,and the first and second bond elements can extend beyond at least oneedge of the chip.

In one example, each of the first, second and third bond elements can bebond wires.

In one example, one of the first and second ends of the first bond wirecan include a ball, and the first end of the second bond wire caninclude a ball. The ball of the second bond wire can be metallurgicallyjoined directly to a first end of the first bond wire.

A microelectronic assembly in accordance with another embodiment of theinvention can include a semiconductor chip having a first face, a secondface remote from the first face, and a plurality of chip contactsexposed at the first face. A substrate can be juxtaposed with one of thefirst or second faces. The substrate may have a plurality of substratecontacts. The assembly may include a first electrically conductive bondelement and a second electrically conductive bond element. Each thefirst and second bond elements can be a bond ribbon. The first andsecond bond elements can electrically connect a first chip contact ofthe plurality of chip contacts with a first substrate contact of theplurality of substrate contacts. The second bond element canelectrically connect the first chip contact with a second substratecontact of the plurality of substrate contacts. The first bond elementcan have a first end metallurgically joined to the first chip contactand a second end metallurgically joined to the first substrate contact,and the second bond element can have a first end metallurgically joinedto the first end of the first bond element. A third electricallyconductive bond element can electrically connect the first substratecontact with the second substrate contact.

A microelectronic assembly in accordance with another embodiment of theinvention can include a semiconductor chip having a first face, a secondface remote from the first face, and a plurality of chip contactsexposed at the first face. A substrate can be juxtaposed with one of thefirst or second faces, the substrate having a plurality of substratecontacts. The assembly can include a first electrically conductive bondwire and a second electrically conductive bond wire, the first andsecond bond wires electrically connecting a first chip contact of theplurality of chip contacts with a first substrate contact of theplurality of substrate contacts. The first bond wire can have a firstend metallurgically joined to the first chip contact and a second endelectrically connected to the first substrate contact. The second bondwire can have a first end metallurgically joined to the first bond wire.The first end of the second bond wire can be arranged such that it doesnot touch the first chip contact.

In one example, the second end of the first bond element can bemetallurgically joined to the first substrate contact.

In a particular example, the second end of the second bond element canbe metallurgically joined to the first substrate contact.

In one example, one of the first and second ends of the first bond wirecan include a ball, and the first end of the second bond wire caninclude a ball. The ball of the second bond wire can be metallurgicallyjoined directly to the first end of the first bond wire.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a microelectronic assembly in accordancewith one embodiment.

FIG. 2 is a corresponding plan view of a microelectronic assembly asseen in FIG. 1, the sectional view of FIG. 1 being taken through line1-1 of FIG. 2.

FIG. 3 is a fragmentary partial sectional view illustrating a connectionbetween bond elements in a microelectronic assembly in an embodimentherein.

FIG. 4 is a fragmentary partial sectional view further illustrating aconnection between bond elements in a microelectronic assembly in anembodiment herein.

FIG. 5 is a fragmentary partial sectional view illustrating a connectionbetween bond elements in a variation of a microelectronic assembly in anembodiment herein.

FIG. 6 is a plan view of a microelectronic assembly in accordance withone embodiment herein.

FIG. 7A is a sectional view of a microelectronic assembly in accordancewith one embodiment herein.

FIG. 7B is a fragmentary partial perspective view of a microelectronicassembly particularly illustrating a lead bond therein.

FIG. 7C is a plan view of a microelectronic assembly in accordance withone embodiment herein.

FIG. 8 is a sectional view of a microelectronic assembly in accordancewith one embodiment herein.

FIG. 9 is a fragmentary partial perspective view of a microelectronicassembly particularly illustrating a looped connection including aribbon bond therein.

FIG. 10 is a sectional view illustrating a microelectronic assembly inaccordance with a variation of the embodiment shown in FIGS. 1 through5.

FIG. 11 is a fragmentary perspective view illustrating a microelectronicassembly in accordance with a variation of the embodiment shown in FIG.10.

FIG. 12A is a fragmentary partial perspective view illustrating amicroelectronic assembly in accordance with a variation of theembodiment shown in FIGS. 1 through 5.

FIG. 12B is a fragmentary partial elevational view illustrating amicroelectronic assembly in accordance with a variation of theembodiment shown in FIG. 12A.

DETAILED DESCRIPTION

As used in this disclosure, a statement that an electrically conductivestructure is “exposed at” a surface of a dielectric structure indicatesthat the electrically conductive structure is available for contact witha theoretical point moving in a direction perpendicular to the surfaceof the dielectric structure toward the surface of the dielectricstructure from outside the dielectric structure. Thus, a terminal orother conductive structure which is exposed at a surface of a dielectricstructure may project from such surface; may be flush with such surface;or may be recessed relative to such surface and exposed through a holeor depression in the dielectric.

Wire bonds and other conductors used to connect a chip to anotherelement, e.g., a substrate within a package, can have many differentshapes and sizes. The wire used in forming wire bonds generally iscylindrical in cross-section. The wires typically are available in twodiameters, 1 mil, or 0.001 inch, and 0.7 mil, or 0.007 inch. Theinductance of a conductor is directly related to its length andinversely related to its cross-sectional area. Accordingly, bond wirestypically have larger inductances than some other types of connectionsbetween a chip and substrate which are shorter or have largercross-sectional area. Bond wires generally have larger inductances thanthe solder connections between a chip and a substrate in a flip-chippackage, since the solder connections usually have larger diameters andshorter lengths than bond wires. Other types of connections between achip and a substrate, such as lead bonds and ribbon bonds, are generallywider than bond wires, but have inductances which can be characterizedin a similar way to wire bonds because of their lengths and relativelysmall cross-sectional areas.

As the number of pads on a chip increases without increasing the outlineof a package, and as the operating frequency increases, it is desirableto provide a way of lowering the inductance of wire bonds in a package.As mentioned, the length and cross-sectional area of each wire bond arefactors which largely determine the inductance. Unfortunately, within agiven package, it is difficult to significantly reduce the length of awire bond. Also, the wire used in wirebonding is available in standarddiameters for use on equipment which is standardized in this respect.Therefore, it would be difficult to form wire bonds using wire that islarger in diameter than the most common standard diameters.

Accordingly, embodiments described herein provide ways of lowering theinductance of a wire bond. In an embodiment seen in FIGS. 1-2, one ofthe ways in which wire bond inductance can be reduced is by connecting acontact of a chip to a contact of a substrate via multiple bond wires.By using multiple bond wires, the cross-sectional area of the connectionfrom the chip contact to the substrate contact is effectively increased,because current can now flow along both bond wires between the contacts.

For example, FIGS. 1-2 illustrate a microelectronic assembly 100 inaccordance with one embodiment herein. The microelectronic assembly 100can include a microelectronic element 110 which is electricallyconnected to a substrate 130. In an embodiment herein, the “substrate”can include a dielectric element bearing a plurality of traces and bondpads. Without limitation, one particular example of a substrate can be asheet-like flexible dielectric element, typically made of a polymer,e.g., polyimide, among others, having metal traces and bond padspatterned thereon, the bond pads being exposed at at least one face ofthe dielectric element.

For ease of reference, directions may be stated in this disclosure withreference to a “top”, i.e., contact-bearing surface 128 of asemiconductor chip 110. Generally, directions referred to as “upward” or“rising from” shall refer to the direction orthogonal and away from thechip top surface 128. Directions referred to as “downward” shall referto the directions orthogonal to the chip top surface 128 and oppositethe upward direction. The term “above” a reference point shall refer toa point upward of the reference point, and the term “below” a referencepoint shall refer to a point downward of the reference point. The “top”of any individual element shall refer to the point or points of thatelement which extend furthest in the upward direction, and the term“bottom” of any element shall refer to the point or points of thatelement which extend furthest in the downward direction.

The substrate 130 typically has an interconnection function. Forexample, the microelectronic subassembly can be an element of a packagehaving a plurality of conductive leads or traces 134, a plurality ofcontacts 132 connected to the leads or traces arranged generally forinterconnection with the microelectronic device, and a plurality ofterminals 136 for interconnection to another element such as forexternal interconnection to a printed circuit board. The contacts 132typically are in form of bond pads exposed at the upwardly directed face131 of the substrate.

As seen in FIGS. 1-2, the chip can be connected to the substrate 130 viawire bond connections. The wire bond connections can include connections140 in which multiple bond wires electrically connect one chip contactto a corresponding substrate contact. In addition, the wire bondconnections can include other wire bond connections 142 in which only asingle bond wire electrically connects a chip contact to a correspondingsubstrate contact.

Connections 140 which include multiple bond wires have a uniquestructure. In this case, as seen in FIG. 1, and as seen in greaterdetail in FIG. 3, a connection can include first and second bond wires144, 146 which connect one chip contact 112 to a corresponding substratecontact 132. For example, the first bond wire 144 can have an end 144Ametallurgically joined with the chip contact 112 and another end 144Bmetallurgically joined with the substrate contact 132. For example, thebond wires can include a metal such as gold which can be welded usingultrasonic energy, heat, or both, to a contact to form a metallurgicaljoint or bond therewith. In contrast, the second bond wire 146 can haveone end 146A metallurgically bonded to the end 144A of the first bondwire 144. The second bond wire 146 can also have one end 146Bmetallurgically bonded to the end 144B of the first bond wire 144.

As seen in FIGS. 1 and 3, the second bond wire 146 need not touch thecontacts 112, 132, i.e., the bond pads, to which the first bond wire 144is metallurgically bonded. Instead, in a particular embodiment, the ends146A, 146B of the second bond wire can be metallurgically bonded to theends 144A, 144B of the first bond wire in such way the that second bondwire does not touch the contact at least one end of the second bond wireand may not touch the contacts at either end.

As seen in FIG. 3, an end 144A, 146A of each bond wire 144, 146 caninclude a ball formed during the wirebonding process. A wirebonding tooltypically operates by advancing the tip of a gold wire from a spool to atip of the tool. In one example of processing, when the tool is inposition for forming a first wire bond at a first contact, e.g., chipcontact 112, the tool can then apply ultrasonic energy, heat or both tothe wire until the tip of the wire melts and forms a ball. The heatedball then metallurgically bonds with a surface of the contact. Then,when the tip of the wirebonding tool is moved away from the firstcontact, the ball remains bonded to the contact, while a length of thebond wire between such contact and a second contact is paid out. Thewirebonding tool can then form another ball at the second end of thewire which is metallurgically joined to the second contact at that end.

The above process can then be repeated in a somewhat different fashionto form the second bond wire. In this case, the wirebonding tool can bemoved into a position, and can then be used to heat the tip of the wireto form a ball which then metallurgically joins an end 146A of thesecond bond wire to the end 144A of the first bond wire. Similarly, whenthe wirebonding tool is in position to form a joint at the other end ofthe bond wire, the wirebonding tool can heat the tip of the wire andform a ball which metallurgically joins the end 146B to the end 144B ofthe bond wire.

In the example illustrated in FIGS. 1, 2, and 3, some of the contacts132 can carry signals, i.e., voltages or currents which vary with timeand which typically convey information. For example, without limitation,voltages or currents which vary with time and which represent state,change, a measurement, a clock or timing input or a control or feedbackinput are examples of signals. Others of the contacts 132 may provideconnections to ground or a power supply voltage. A connection to groundor a power supply voltage typically provides a voltage which is at leastfairly stable with time over frequencies of interest to the operation ofthe circuit.

One possible benefit of a multiple bond wire structure and methodaccording to this embodiment is to reduce inductance when area forattaching a bond wire to a contact such as a bond pad on a chip or asubstrate is limited. Some chips have particularly high contact densityand fine pitch. The bond pads on such chips have very limited area. Astructure in which a second bond wire has an end attached to an end of afirst bond wire but which itself does not touch the contact can achievea dual or multiple bond wire structure without requiring the size of thebond pad to be increased. Thus, a multiple bond wire structure asdescribed with respect to FIGS. 1, 2 and 3 may be achieved even whenforming wire bond connections to contacts which are arranged at a finepitch or contacts which have small area.

Moreover, some such chips having high density also have high input andoutput rates, i.e., high frequencies at which signals are transmittedonto or off of the chip. At sufficiently high frequencies, theinductance of a connection can increase substantially. A multiple bondwire structure according to this embodiment can substantially decreaseinductance of a wire bond connection by providing an additional path forcurrent to flow between the connected contacts.

FIG. 4 illustrates connections between a first bond wire 244 and asecond bond wire 246 at ends thereof. As seen in FIG. 4, at first endsof the bond wires, the balls 244A and 246A can be metallurgically joinedtogether, but in such manner that the ball of the second wire 246A doesnot touch the contact 212A. At second ends 244B, 246B of the bond wiresat a second contact 212B, electrical connection can be made between thewires without balls being formed at the second ends 244A, 244B. In thiscase, one of the contacts 212A, 212B can be a chip contact exposed at asurface of the chip, and another one of the contacts 212A, 212B can be asubstrate contact exposed at a surface of the substrate. Alternatively,both of the contacts 212A, 212B can be chip contacts or both contacts212A, 212B can be substrate contacts.

FIG. 5 illustrates a variation of such embodiment (FIG. 4) in which, ata first contact, the first bond wire 344 has a ball end 344A joinedthereto. A wire end 346A of the second bond wire 346 is metallurgicallyjoined to the ball end 344A of the first bond wire above the firstcontact 212A. In addition, at the second contact 212B, a ball end 346Bof the second bond wire 346 is metallurgically joined to a wire end 344Bof the first bond wire 344.

In another variation of the above-described embodiments, a plurality ofbond wires can be formed and joined with a bond wire which is joined tothe contacts at ends thereof to form three or more parallel pathsbetween the contacts. In this embodiment, a third bond wire can bearranged such that the joints between it and first or second bond wires(e.g., wires 244, 246 (FIG. 4) or wires 344, 346 (FIG. 5) do not touchthe contacts to which ends of the first bond wire are joined. Ifdesired, an even greater number of bond wires can be used which aremetallurgically joined in this manner to other bond wires, so as toprovide parallel electrical paths for current to flow between a pair ofcontacts.

FIG. 6 illustrates a variation of the above-described embodiments inwhich a bond wire 446 is seen connected, i.e., metallurgically joined,to the ends of bond wires 444, 445 which are connected to two adjacentsubstrate contacts 132A and 132B. The additional bond wire 446 can beformed in a manner according to the embodiments described above (FIGS.1-5). Again, the bond wire 446 need not touch the contacts 132A, 132B towhich the first bond wires 444, 445 are metallurgically joined. Rather,an end of bond wire 446 can be joined to the end of another bond wire444 which itself is joined to the contact, as seen for example, in FIG.3, 4 or 5. Also, another end of bond wire 446 can be joined in similarmanner to the end of bond wire 445 which is joined to the contact. Asalso seen in FIG. 6, in one variation, a similarly joined bond wire 448can be joined to the ends of bond wires connected to non-adjacentsubstrate contacts 132C, 132D, such that it skips over a contact 132Ethat lies between the two contacts 132C, 132D. As further seen in FIG.6, bond wires 450, 452 can be joined in similar manner to the ends ofthe other bond wires at the chip contacts. For example, bond wire 450 isjoined to the ends of other bond wires which, in turn, are joined tocontacts 412A and 412B.

FIGS. 7A-7B illustrate another embodiment in which lead bonds 544 areprovided on a substrate 530, the lead bonds extending from a surface ofthe substrate 530 to the contacts 512 of the chip where they aremetallurgically joined thereto. As seen in the fragmentary perspectiveview provided in FIG. 7B, a lead bond typically is a long and flatelement, having a length extending in a direction towards a chip contact512 to which it is joined. The lead bond can have a width 550 extendingin a direction transverse to its length, and a thickness 554 extendingin a direction from the substrate surface. The length of a lead bondusually is greater than its width. The width of a lead bond usually isgreater than its thickness. As seen in FIG. 7A, bond wires 546 can haveends joined to the lead bonds 544 at locations above the chip contactsand at locations above the substrate, in such manner that the bond wires546 do not touch the contacts to which the lead bonds are joined. Insuch manner, the bond wires can provide parallel paths for current whichcan help lower the inductance of the lead bond connections between thesubstrate and the chip.

As further seen in FIG. 7C, in place of bond wires, it is possible touse other forms of bond elements to form parallel current paths betweencontacts. For example, a bond ribbon 646 can be used as an additionalbond element joined to ends of a lead bond 644 that is joined to a chipcontact 612 and a corresponding substrate contact 632, such that thebond ribbon 646 does not touch the contacts 612, 632. Like a lead bond,a bond ribbon 646 typically is a long and flat element, which, in likemanner has a length extending in a direction to or from the chip contact612 and a width extending in a direction transverse to length, and athickness extending in a direction away from a surface to which it isjoined, i.e., a surface of a lead bond to which it is joined. The widthof the bond ribbon usually is greater than the thickness. A bond ribbontypically can be formed by a ribbon bonding tool in a manner similar tothe process described above for forming bond wires.

In another variation, a bond ribbon 648 can be metallurgically joined toadjacent lead bonds 650, 652 above the substrate surface. In anothervariation, a bond ribbon 656 can be metallurgically joined to the endsof the adjacent lead bonds 658, 660 which are bonded to the chipcontacts.

FIG. 8 illustrates a variation of the above-described embodiment (FIGS.1-2) in which a bond wire 740 has a looped connection, wherein two runsof the same bond wire extend between and are electrically connected to apair of contacts. In this embodiment, a first ball end 742 can bemetallurgically joined to one of the contacts (e.g., a substrate contact732A). The bond wire 740 has a middle portion 744 which ismetallurgically joined to the chip contact 712A, and has a second end746 joined to the ball end 742 of the bond wire 740, in such manner thatthe second end 746 does not touch the contact 732A. In such manner, asingle bond wire can be used to form parallel current paths between thesame two contacts.

In one variation, FIG. 8 also shows an embodiment in which the secondend 756 of one bond wire 750 is joined to the same contact 732B to whicha first end 752 of the bond wire is joined. However, in this case, thesecond end 756 does touch the contact 732B, and can be joined directlythereto. In other embodiments, not shown, a similar looped connectioncan be made between two contacts of the substrate using a bond wirehaving a middle portion joined to one of the substrate contacts and endsjoined to another one of the substrate contacts or having ends joinedtogether with at least one of the ends joined to the substrate contact.In yet another variation, a similar looped connection can be madebetween two contacts of a chip using a bond wire having a middle portionjoined to one of the chip contacts and ends joined to another one of thechip contacts, or having ends joined together with at least one of theends joined to the chip contact.

FIG. 9 illustrates a variation similar to FIG. 8 in which a bond ribbon840 is used instead of a bond wire, wherein the bond ribbon 840 has afirst end 842 metallurgically joined to one of the contacts (e.g.,contact 832A). The bond wire 840 has a middle portion 844 which ismetallurgically joined to another contact 832B, and has a second end 846joined to the first end 842 of the bond ribbon. The joint between thefirst and second ends 842, 846 of the bond ribbon can be such that thesecond end 846 does not touch the contact 832A to which the first end isjoined. Alternatively, in one variation (not shown), the second end 842can touch or be joined directly with the same contact 832A to which thefirst end 846 is joined, similar to the arrangement of bond wire 750 inFIG. 8. One of the contacts, e.g., one of contacts 832A, 832B can be asubstrate contact and another one of the contacts 832A, 832B can be achip contact. Alternatively, both of the contacts 832A, 832B can besubstrate contacts exposed at a surface of a substrate, or both contacts832A, 832B can be chip contacts exposed at a surface of a chip.

In a variation (FIG. 10) of the above-described embodiment (FIGS. 1through 5), a microelectronic assembly 900 can include first and secondbond elements 944, 946, each being a bond wire, or alternatively, a bondribbon, and each having first ends 944A, 944B electrically connected toa first chip contact 112 exposed at a first face 128 of a semiconductorchip 110. A substrate 130 is juxtaposed with the first face 128 of thechip 130, the substrate having an opening 920 exposing a plurality ofchip contacts including first chip contact 112, such that the first andsecond bond elements 944, 946 extend through the opening in thesubstrate. Second ends 944A, 946B of the bond elements can beelectrically connected to respective substrate contacts exposed at aface 131 of the substrate 130.

As further seen in FIG. 10, the first bond element can have a first end944A metallurgically joined to the first chip contact and a second end944B electrically connected or metallurgically joined to the firstsubstrate contact 932A. Stated another way, the ends of the first bondelement can be joined via a metal to metal joining process, with metalat the ends of the first bond element forming joints with metal of thefirst chip contact and first substrate contact. In addition, as furtherseen in FIG. 10, the second bond element can have a first end 946A whichis metallurgically joined to the first bond element 944 and a second end946B electrically connected or metallurgically joined to a secondsubstrate contact 932B. The second bond element can be joined to thefirst bond element metallurgically, i.e., via a metal to metal joiningprocess, with metal at the ends of the first and second bond elementsforming a metal to metal joint. In a particular embodiment, as seen inFIG. 10, an end 946A of the second bond element 946 is joined with anend 944A of the first bond element 944. In a particular embodiment, asseen in FIG. 10, the second bond element 946 does not touch the firstchip contact 112. Stated another way, the second bond element can bewholly separated from a surface of the first chip contact by the firstbond element to which the second bond element is joined.

As particularly shown in FIG. 10, a ball end 946A of the second bondelement is joined with a ball end 944A of the first bond element.However, alternatively, the first and second bond elements can be joinedin accordance with the variation shown in FIG. 5.

As further seen in FIG. 10, a third electrically conductive bond element948 can electrically connect the first substrate contact 932A with thesecond substrate contact 932B. The third bond element can bemetallurgically joined to a second end 944B, or 946B of at least one ofthe first and second bond elements. In one embodiment, the ends 948A,948B of the third bond element can be metallurgically joined to thesecond ends 944B, 946B of each of the first and second bond elements. Ina particular embodiment, similar to the arrangement of the first end946A of the second bond element relative to the first chip contact 112,the third bond element need not touch any of the first or the secondsubstrate contacts 932A, 932B to which the first and second bondelements are joined. Alternatively, the third bond element can be asshown at 950 in which ends of the third bond are metallurgically joinedto the first and second substrate contacts 932A, 932B.

FIG. 11 illustrates a variation of the embodiment described above withreference to FIG. 10, in which the chip 1110 has a first face 128 withcontacts 1112 exposed thereat, the chip having a second face 129 remotefrom the first face and a peripheral edge 1114 which extends between thefirst and second faces 128, 129. As seen in FIG. 11, the second face isjuxtaposed with substrate 1130. As in the above-described embodiment(FIG. 10), first and second bond elements 1144, 1146 can have endsjoined to each other; however, the second bond element need not touchthe first chip contact 1112 to which the first bond element ismetallurgically joined. The first and second bond elements 1144, 1146can extend beyond the peripheral edge 1114 of the chip 1110. The firstand second bond elements are metallurgically joined to respective firstand second substrate contacts 1132A, 1132B exposed at a surface 1131 ofthe substrate.

FIG. 11 illustrates that a third bond element 1150 can electricallyconnect the first and second substrate contacts 1132A, 1132B. Theconnections between the third bond element and the first and secondsubstrate contacts can be as described above with respect to FIG. 10.

FIG. 12A illustrates a microelectronic assembly in accordance with avariation of the embodiment described above with respect to FIGS. 1-5.In this variation, first and second bond elements 1244, 1246 have firstends 1144A, 1144B metallurgically joined together, as described above(FIGS. 1-5), wherein the first bond element 1244 is joined to a chipcontact 112 exposed at a face of a semiconductor chip (not shown). Asseen in the particular view of FIG. 12A, the bond elements can be bondwires and each first end 1244A, 1246A can include a ball. The secondbond element 1246 (e.g., an end 1246A thereof) does not touch the firstchip contact 112. As further seen in FIG. 12, second ends 1244B, 1246Bof each of the first and second bond elements are metallurgically joinedto a substrate contact 132 exposed at a surface of a substrate (notshown).

In a variation of the embodiment shown in FIG. 12A, each of the bondelements 1244, 1246 can be a bond wire and each first end 1244A, 1246Acan be a wire end which is remote from the ball end of the bond wire,i.e., the end which includes a ball. In such variation, the first endscan resemble the wire ends 244B, 246B of the bond wires seen in FIG. 4.In a particular variation, the second end 1244B, 1246B of each bond wireincludes a ball, each second end 1244B, 1246B being joined to thesubstrate contact 132.

In yet another variation of the embodiment shown in FIG. 12A, each ofthe bond elements can be a bond wire and the first ends 1244A, 1246A ofthe bond wires can be metallurgically joined together in a mannersimilar to the ends: ball end 344A, and wire end 346A of the first andsecond bond wires shown in FIG. 5. Specifically, a first end 1244A ofone bond wire can include a ball and a first end 1246A of a second bondwire metallurgically joined thereto can include a wire end which isremote from the ball end of the second bond wire. Each of the secondends of the bond wires is joined to the substrate contact, as seen inFIG. 12A.

As seen in FIG. 12B, in one variation of the above embodiment (FIG.12A), the ends 1254A, 1254B of the bond elements 1254 and 1256 can bemetallurgically joined to each other and also joined to the contact 112.In a specific embodiment as shown in FIG. 12B, each bond element can bea bond wire and the ball ends 1254A, 1256A of the bond wires can bemetallurgically joined to the chip contact 1212 and to each other.Similar to the variations discussed above with respect to FIG. 12A, infurther variations of that shown in FIG. 12B, the first ends 1254A,1256A of the bond wires can be wire ends, or an end of a first bond wirecan be a ball end and an end of a second bond wire can be a wire end,the first ends being metallurgically joined to each other and to thechip contact 1212.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1. A microelectronic assembly, comprising: a semiconductor chip having afirst face, a second face, and a plurality of chip contacts exposed atthe first face; a substrate juxtaposed with one of the first or secondfaces, the substrate having a plurality of substrate contacts exposed ata face of the substrate; and a first electrically conductive bond wireand a second electrically conductive bond wire, the first and secondbond wires electrically connecting a first chip contact of the pluralityof chip contacts with a corresponding first substrate contact of theplurality of substrate contacts and providing parallel conductive pathsbetween the first chip contact and first substrate contact, the firstbond wire having a first end metallurgically joined to the first chipcontact and a second end metallurgically joined to the first substratecontact, wherein one of the first and second ends of the first bond wireincludes a ball, and one of the first and second ends of the second bondwire includes a ball, the ball of the second bond wire beingmetallurgically joined directly to one of the first and second ends ofthe first bond wire, an end of the second bond wire remote from the ballof the second bond wire is metallurgically joined to the ball of thefirst bond wire, and wherein the second bond wire does not touch eitherthe first chip contact or the first substrate contact.
 2. Amicroelectronic assembly, comprising: a semiconductor chip having afirst face, a second face, and a plurality of chip contacts exposed atthe first face; a substrate juxtaposed with one of the first or secondfaces, the substrate having a plurality of substrate contacts thereon; afirst electrically conductive bond element connecting a first pair of asubstrate contact and a chip contact, the first bond element being oneof a lead bond or a bond wire; a second electrically conductive bondelement connecting a second pair of a substrate contact and a chipcontact, the second bond element being one of a lead bond or a bondwire; and a third electrically conductive bond element joined to ends ofthe first and second bond elements, wherein the third bond element doesnot touch the chip contact or the substrate contact of either the firstor second pairs, wherein the third bond element is one of a ribbon bondor a bond wire.
 3. A microelectronic assembly as claimed in claim 2,wherein the joints of the third bond element with the first and secondbond elements are adjacent the chip contacts of the first and secondpairs.
 4. A microelectronic assembly as claimed in claim 2, wherein thejoints of the third bond element with the first and second bond elementsare adjacent the substrate contacts of the first and second pairs.
 5. Amicroelectronic assembly as claimed in claim 2, wherein each of thefirst, second and third bond elements are bond wires.
 6. Amicroelectronic assembly as claimed in claim 2, wherein the first andsecond bond elements are lead bonds and the third bond element is a bondwire.
 7. A microelectronic assembly, comprising: a semiconductor chiphaving a first face, a second face, and a plurality of chip contactsexposed at the first face; a substrate juxtaposed with one of the firstor second faces, the substrate having a plurality of terminals thereonand a plurality of leads electrically connected with the terminals andextending away therefrom, a first lead of the plurality of leads havingan end bonded to a first chip contact of the plurality of chip contacts;and a bond wire having a first end metallurgically joined to the end ofthe first lead, the bond wire not touching the first chip contact, thebond wire having a second end metallurgically joined to the first leadat a location spaced apart from the first chip contact.
 8. Amicroelectronic assembly as claimed in claim 7, wherein the second endof the bond wire is joined to the first lead at a location where thefirst lead overlies the substrate.
 9. A microelectronic assembly,comprising: a semiconductor chip having a first face, a second face, anda plurality of chip contacts exposed at the first face; a substratejuxtaposed with one of the first or second faces, the substrate having aplurality of substrate contacts thereon; and a plurality of electricallyconductive bond elements including a first bond element, the first bondelement being a bond ribbon or a bond wire electrically connecting apair of contacts, the pair including a chip contact of the plurality ofchip contacts and a corresponding substrate contact of the plurality ofsubstrate contacts, the first bond element having first and second endselectrically connected to a first contact of the pair of the contacts,and a middle portion between the first and second ends metallurgicallyjoined with the second contact of the pair of contacts, such that thefirst bond element extends in a continuous loop from the first end atthe first contact, through the middle portion joined to the secondcontact and back to the second end connected to the first contact.
 10. Amicroelectronic assembly as claimed in claim 9, wherein the second endis joined to the first end and does not touch the first contact.
 11. Amicroelectronic assembly as claimed in claim 9, wherein each of thefirst and second ends is joined directly to the first contact.
 12. Amicroelectronic assembly as claimed in claim 10, wherein the at leastone bond element is a bond wire.
 13. A microelectronic assembly asclaimed in claim 10, wherein the at least one bond element is a bondribbon.
 14. A microelectronic assembly, comprising: a semiconductor chiphaving a first face, a second face, and a plurality of chip contactsexposed at the first face; a substrate juxtaposed with one of the firstor second faces, the substrate having a plurality of substrate contactsexposed at a face of the substrate; and a first electrically conductivebond element and a second electrically conductive bond element, thefirst and second bond elements each being one of a bond ribbon or a bondwire, the first and second bond elements electrically connecting a firstchip contact of the plurality of chip contacts with a correspondingfirst substrate contact of the plurality of substrate contacts andproviding parallel conductive paths between the first chip contact andthe first substrate contact, the first bond element having a first endmetallurgically joined to the first chip contact and a second endmetallurgically joined to the first substrate contact, the second bondelement being metallurgically joined to the first and second ends of thefirst bond element.
 15. A microelectronic assembly, comprising: asemiconductor chip having a first face, a second face remote from thefirst face, and a plurality of chip contacts exposed at the first face;a substrate juxtaposed with one of the first or second faces, thesubstrate having a plurality of substrate contacts; and a firstelectrically conductive bond element and a second electricallyconductive bond element, the first and second bond elements each beingone of a bond ribbon or a bond wire, the first bond element electricallyconnecting a first chip contact of the plurality of chip contacts with afirst substrate contact of the plurality of substrate contacts, thesecond bond element electrically connecting the first chip contact witha second substrate contact of the plurality of substrate contacts,wherein the first bond element has a first end metallurgically joined tothe first chip contact and a second end electrically connected to thefirst substrate contact, and the second bond element has a first endmetallurgically joined to the first end of the first bond element sothat that the second bond element does not touch the first chip contact.16. A microelectronic assembly as claimed in claim 15, wherein each ofthe first and second bond elements is a bond wire.
 17. A microelectronicassembly as claimed in claim 16, wherein one of the first and secondends of the first bond wire includes a ball, and the second bond wireincludes a ball, wherein the ball of the second bond wire ismetallurgically joined to the ball of the first bond wire.
 18. Amicroelectronic assembly as claimed in claim 16, wherein one of thefirst and second ends of the first bond wire includes a ball, the secondbond wire has a first end including a ball and a second end remotetherefrom, the second end of the second bond wire being metallurgicallyjoined to the ball of the first bond wire.
 19. A microelectronicassembly as claimed in claim 15, wherein at least one of the first orsecond bond elements is a bond ribbon.
 20. A microelectronic assembly asclaimed in claim 15, further comprising a third electrically conductivebond element electrically connecting the first substrate contact withthe second substrate contact.
 21. A microelectronic assembly as claimedin claim 20, wherein the third bond element is metallurgically joined toa second end of at least one of the first and second bond elements. 22.A microelectronic assembly as claimed in claim 21, wherein the thirdbond element is metallurgically joined to the second ends of each of thefirst and second bond elements.
 23. A microelectronic assembly asclaimed in claim 22, wherein the third bond element does not touch anyof the first or the second substrate contacts to which the first andsecond bond elements are bonded.
 24. A microelectronic assembly asclaimed in claim 20, wherein the third bond element is metallurgicallyjoined to the first and second substrate contacts.
 25. A microelectronicassembly as claimed in claim 15, wherein the substrate overlies thefirst face of the chip and has an opening exposing the plurality of chipcontacts, wherein the first and second bond elements extend through theopening in the substrate.
 26. A microelectronic assembly as claimed inclaim 15, wherein the second face of the chip overlies the substrate,wherein the first and second bond elements extend beyond at least oneedge of the chip.
 27. A microelectronic assembly, comprising: asemiconductor chip having a first face, a second face remote from thefirst face, and a plurality of chip contacts exposed at the first face;a substrate juxtaposed with one of the first or second faces, thesubstrate having a plurality of substrate contacts; and a firstelectrically conductive bond wire and a second electrically conductivebond wire, the first and second bond wires electrically connecting afirst chip contact of the plurality of chip contacts with a firstsubstrate contact of the plurality of substrate contacts, the secondbond wire electrically connecting the first chip contact with a secondsubstrate contact of the plurality of substrate contacts, wherein thefirst bond wire has a first end metallurgically joined to the first chipcontact and a second end metallurgically joined to the first substratecontact, and the second bond wire has a first end metallurgically joinedto the first end of the first bond wire.
 28. A microelectronic assemblyas claimed in claim 27, wherein the second bond wire has a first endmetallurgically joined to the first chip contact.
 29. A microelectronicassembly as claimed in claim 27, further comprising a third electricallyconductive bond element electrically connecting the first substratecontact with the second substrate contact.
 30. A microelectronicassembly as claimed in claim 29, wherein the third bond element ismetallurgically joined to a second end of at least one of the first andsecond bond wires.
 31. A microelectronic assembly as claimed in claim30, wherein the third bond element is metallurgically joined to thesecond ends of each of the first and second bond wires.
 32. Amicroelectronic assembly as claimed in claim 29, wherein the third bondelement is metallurgically joined to the first and second substratecontacts.
 33. A microelectronic assembly as claimed in claim 30, whereinthe substrate overlies the first face of the chip and has an openingexposing the plurality of chip contacts, wherein the first and secondbond wires extend through the opening in the substrate.
 34. Amicroelectronic assembly as claimed in claim 30, wherein the second faceof the chip overlies the substrate, wherein the first and second bondwires extend beyond at least one edge of the chip.
 35. A microelectronicassembly as claimed in claim 27, wherein one of the first and secondends of the first bond wire includes a ball, and the first end of thesecond bond wire includes a ball, the ball of the second bond wire beingmetallurgically joined directly to the first end of the first bond wire.36. A microelectronic assembly, comprising: a semiconductor chip havinga first face, a second face remote from the first face, and a pluralityof chip contacts exposed at the first face; a substrate juxtaposed withone of the first or second faces, the substrate having a plurality ofsubstrate contacts; and a first electrically conductive bond element anda second electrically conductive bond element, each of the first andsecond bond elements being a bond ribbon, the first and second bondelements electrically connecting a first chip contact of the pluralityof chip contacts with a first substrate contact of the plurality ofsubstrate contacts, the second bond element electrically connecting thefirst chip contact with a second substrate contact of the plurality ofsubstrate contacts, wherein the first bond element has a first endmetallurgically joined to the first chip contact and a second endmetallurgically joined to the first substrate contact, and the secondbond element has a first end metallurgically joined to the first end ofthe first bond element; and a third electrically conductive bond elementelectrically connecting the first substrate contact with the secondsubstrate contact.
 37. A microelectronic assembly as claimed in claim29, wherein the third bond element is a bond wire.